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Crop genetics

What is crop genetics?

The science of genomics studies the entire DNA sequence of an organism, which covers all the chromosomes. Knowing the DNA sequence guides decisions about how to solve problems faced by that organism. In humans, genomics is used to study disease and seek cures. In plants, it is used to determine the best genes to be selected in improved crop varieties. The final goal is to predict which plants will perform best, and under which conditions. This allows plant breeders to select plants most adapted to farmers’ needs.

How does this affect me?

Fertilizing a sweet potato plant using tweezersTraditional plant breeding can take years – or even decades, if you are breeding trees – to develop new crop varieties. (Read more about one plant's challenges, here.) Genomics allows scientists to identify which genes control important traits in a plant. They can determine which changes in the DNA sequence improve that trait. New technologies enable scientists to quickly study thousands of genes in thousands of plants. This allows plant breeders to choose, from a wide selection, the plants with the best DNA sequence at many genes and for many traits at the same time. This can often be done from a seed or seedling, instead of waiting for the plant to mature and show the desired leaf, flower, or fruit characteristics. (Read about one bean's adventure, here.)

Current challenges

Plant breeders are studying the genomics of plants to determine how to increase yields. They also study traits that make plants more (or less) resilient to various environmental conditions, like heat and drought. Studying genomics allows scientists to look at how plants respond to disease and insect stresses. It can even help predict plants that will have higher nutritional quality (see the Nutritional Quality section, here). Identifying the genes, and the exact DNA sequence differences, that affect these traits can be slow and expensive. Once these DNA sequences are identified, however, selecting improved plants becomes much more efficient. Sharing information on which sequences affect which traits makes the work of all breeders and geneticists go faster.

Making use of advances in genomics requires that plant breeders become savvy in working with vast amounts of data. That means they need to develop better methods to store, share, and quickly analyze data. Managing the data will help produce significant advances in plant breeding (see an example here).

What advances have we seen in crop genetics?

Corn cobs of different colors, size, shape!Researchers Watson and Crick discovered a way to determine the structure of DNA in 1953. In 1977, Frederick Sanger and colleagues developed a method to read the order of the base pairs, or the letters of the genetic code. Since then, ever faster methods to read the sequence and the changes in the base pairs have been developed. Genetic markers now allow the detection of single changes at known places along chromosomes. This allows scientists to know which sequences along the chromosome control which traits!

Sequencing of very long pieces of DNA, up to entire genomes of organisms, is now possible. This allows scientists to learn how each gene works together with all other genes in the organism’s genome to create its final phenotype. A plant’s phenotype would be its appearance and how it grows and responds to changes in the environment and to other organisms including insect or disease pests, beneficial insect or animal pollinators, helpful symbionts, etc. (Read more here.)

Future opportunities

Advancing genomic technologies are making the direct editing of the DNA of crops possible for many plant breeders. If you could, imagine a piece of ribbon with many sections. Perhaps a particular section of ribbon is worn or causing problems. It’s possible to cut that part of the ribbon out and sew a new piece back in. Gene editing will work like this. Scientists can determine which genes make a plant more prone to disease, or make it too tall or floppy for easy harvesting. They will then be able to “edit” the genes, to produce plants with desirable traits. It’s a very precise science, editing only for one or two traits.

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